This invention relates generally to adaptor fittings for electrical wall outlets, and more particularly to adaptor fittings of the type capable of accommodating multiple three-prong electrical plugs, wherein one of the prongs serves to provide a grounding circuit for the electrical appliance being used.
In the past a number of devices have been proposed and produced for expanding the circuit capacity of existing wall outlets. One of the most common devices is known as a "cube tap", which is a small cube-shaped adaptor having two prongs extending from one side and adapted to be inserted in a wall outlet, and sockets on other faces respectively of the cube, adapted to receive electrical plugs. The most common type of cube tap employs a single pair of prongs together with three sockets. While such devices operated in a generally satisfactory manner, there was no provision for accepting electrical plugs having a third grounding pin or prong. Nor did the cube tap itself have such a grounding prong. As a result, their use with appliances such as electric saws, electric drills, etc. was somewhat hazardous, particularly where the device was intended to be used out of doors.
Most appliances which are manufactured today include a third wire in the electrical cord, connected to the casing of the appliance for grounding the same. However, many of the older standard wall outlets provide only two circuits, and thus are not adaptable to receive three-pronged plugs. In an effort to overcome this, several cube taps have been developed with provision for accepting grounding prongs. Such devices included a pigtail having a lug adapted to be received under the grounded wall plate mounting screw of the outlet. However, in many cases the user did not take the necessary time to loosen the mounting screw and insert the grounding lug thereunder. Under such circumstances, the safety feature provided by the three wire cord was completely defeated.
More recently, the Federal Government instituted a set of rules and regulations affecting and regulating the safety of office buildings and manufacturing facilities, in what is known as the Occupational Safety and Health Act (OSHA). Such regulations now require that all outlets and receptacles in manufacturing plants be of the grounded variety. These new regulations pose significant problems in older installations employing two-circuit outlets, since compliance requires removal of the old outlet and installation of new ones having three-circuit sockets. Since such wiring changes must be made by licensed electricians, these operations tend to be extremely costly. As a result, many companies have not undertaken the necessary modifications and are thus in violation of the present OSHA regulations. Such violations are currently resulting in fines of hundreds of dollars per violation when OSHA inspectors visit a particular plant or facility.